question about mbp best battery practices
Recently I had my mbp ('11) serviced for a battery that had stopped retaining charge about 20 months after purchase. The battery had gone through about 40 charge-discharge cycles; my laptop spends most of its time in my office or at home so I use it mostly on AC power. The rep at the genius bar insisted that my battery failed because I didn't use it enough, and he said that the battery needed regular exercise to stay healthy. Since I had never heard of lithium polymer batteries breaking so early from underuse, I did some homework.
-Apple recommends (http://www.apple.com/batteries/notebooks.html) to use at least one charge-discharge cycle per month, and I certainly met that requirement. When I brought this up to the Genius, however, he said that guideline was too low, and recommended that I average around 300 cycles per year.
-According to sources such as this or this, there seems to be no physical justification for exercising my battery regularly as the rep suggested.
By the way, Apple covered the repair under warranty, so they seemed to think the battery was defective and didn't just die from normal use.
So my question is, did the rep know what he was talking about? Are there reasons why I need to cycle my battery anywhere near 300 times per year to keep it healthy? References would be greatly appreciated.
Comments
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
but to cycle it every 3 months for calibration:
http://batteryuniversity.com/learn/article/battery_calibration
This site suggests not keeping it plugged in for extended periods of time:
http://www.laptopbatteryexpress.com/Laptop-Battery-Batteries-FAQs-s/11929.htm
Both suggest small discharge/recharge cycles are best and never go all the way down. 40 cycles in 20 months seems like it would be ok.
The charge/discharge process involves chemical reactions so I doubt that it would be all that predictable from one battery to another to be able to say what the best usage routine would be. The Mac laptops do routine small discharges themselves anyway.
There's no harm in discharging more often than you did with the last battery, the MBP batteries have 1000 cycles before they drop in capacity so using it on battery once or twice a week would be fine. Whether it will improve the lifespan of your particular battery is anyone's guess.
Thanks for your input. I'm not afraid of using my battery more but I just rarely have the occasion to.